A cannabis high from smoking or vaping typically lasts up to 6 hours, while edibles can keep you feeling effects for 6 to 8 hours. But “how long weed affects you” has a longer answer than just the high itself. Residual effects on coordination and mental sharpness can linger well after you feel sober, and THC stays detectable in your body for days or even weeks.
How Long the High Lasts When You Smoke or Vape
Inhaled cannabis hits fast. You’ll feel something within seconds to a few minutes, and the full effects peak within about 30 minutes. From there, the high gradually fades, with most people feeling back to baseline within 3 to 4 hours, though effects can stretch up to 6 hours depending on how much you consumed and how potent the product was.
Some residual effects, like mild grogginess, slower reaction times, or a foggy feeling, can persist for up to 24 hours after a single session. Most people don’t notice these subtle leftovers, but they can still show up on performance tests measuring reaction time and attention.
How Long Edibles Keep You High
Edibles follow a completely different timeline. They typically take 30 to 60 minutes to kick in because THC has to pass through your digestive system and liver before reaching your bloodstream. Peak blood levels hit around 3 hours after you eat or drink a cannabis product, which is when you’ll feel the strongest effects.
The total high from an edible generally lasts 6 to 8 hours, significantly longer than smoking. This is one reason edibles catch people off guard. If you eat a gummy, feel nothing after 45 minutes, and take more, you may end up with a much more intense and longer-lasting experience than you planned for. The slow onset and extended duration also mean the comedown is more gradual, with lingering drowsiness or mild cognitive fog sometimes stretching into the next day.
Impairment Lasts Longer Than the High
This is the part most people underestimate. You can feel completely sober while your motor skills, reaction time, and judgment are still measurably affected. Health Canada recognizes that cannabis can impair mental alertness and physical coordination for up to 24 hours after use. The gap between “I feel fine” and “I’m actually performing normally” is real and can be significant.
Driving guidelines reflect this concern. Colorado’s Department of Transportation recommends waiting at least 6 hours after smoking cannabis with less than 35 mg of THC before driving, and at least 8 hours after eating an edible with less than 18 mg. Higher doses require longer waits. The College of Family Physicians of Canada offers similar numbers: 6 hours minimum after inhaling, 8 hours after oral consumption, with the caveat that impairment may well last longer. Some occupational health guidelines recommend waiting a full 24 hours before operating vehicles or equipment.
Mixing cannabis with alcohol makes everything worse. The two substances amplify each other’s effects, meaning both the high and the impairment window stretch further. Products from unregulated markets can also produce effects lasting longer than 12 hours due to unpredictable potency.
What Determines How Long You Feel It
Several factors shift the timeline in either direction. The biggest ones are dose and method of consumption, but your body also plays a major role.
- Dose and potency: More THC means a longer, stronger experience. A single puff of lower-potency flower fades faster than a deep session with a high-THC concentrate.
- Body fat: THC is fat-soluble, meaning it gets absorbed into fatty tissue throughout your body. People with higher body fat percentages tend to store more THC, which can subtly extend both the active effects and the time it takes to fully clear your system.
- Tolerance: Regular cannabis use causes your brain to dial down its sensitivity to THC. Chronic users often experience shorter, less intense highs from the same dose that would floor an occasional user. This doesn’t mean the drug clears faster, just that your brain responds less dramatically to it.
- Metabolism: A faster metabolism processes THC more quickly, which can shorten the duration of effects. Individual variation here is significant.
How Long THC Stays in Your Body
Feeling sober and testing clean are two very different things. Because THC dissolves into fat, your body releases it slowly over days or weeks rather than clearing it all at once. Drug tests don’t look for THC itself but for a byproduct your liver creates when breaking it down.
Urine Tests
Urine testing is the most common method, and detection windows vary dramatically based on how often you use cannabis. For a single use, you’ll typically test positive for about 3 to 4 days at the standard cutoff level (50 ng/mL). At a more sensitive cutoff (20 ng/mL), that window extends to about 7 days.
For regular users, the math changes considerably. Chronic use is unlikely to produce a positive result beyond 10 days at the standard cutoff, or 21 days at the lower cutoff. In rare cases involving years of very heavy, daily use, detection at 30 days is possible at the more sensitive threshold. The often-cited “weed stays in your system for a month” applies only to these extreme scenarios, not to occasional users.
Other Test Types
Blood tests detect THC for a shorter window, typically 1 to 2 days for occasional users, though chronic use can extend this. Saliva tests generally pick up recent use within 24 to 72 hours. Hair tests have the longest window, potentially detecting use from the past 90 days, though they’re less common and primarily used in specific employment screenings.
The Day-After Effects
Many people report a “weed hangover” the morning after heavy use. This isn’t as well-studied as alcohol hangovers, but common complaints include brain fog, sluggishness, mild headaches, and dry eyes. These tend to resolve within a few hours of waking, especially with hydration and food. The effect is more pronounced with edibles and high-dose sessions, partly because THC is still being slowly released from fat stores and metabolized while you sleep.
For occasional users, this next-day cloudiness is usually minor. For daily users, it can become a persistent baseline that’s hard to notice until you take a break. The cognitive fog that chronic users sometimes describe, often called “burnout,” tends to lift within a few days to a couple of weeks of stopping use, as stored THC gradually clears from fatty tissue.